The repair of damaged automobiles has long been a costly problem, particularly with respect to rusting.
Automobiles have a particular tendency to rust in the pinchweld or channel in which the windshield is mounted, if there is any break in the seal. The pinchweld is defined by the periphery of sheet metal portions of the automobile around the windshield opening, including the leading edge of the roofline, the cowl line and the oppositely disposed windshield pillars. The construction is identical regardless of whether the front or rear light or windshield is considered. The windshield is installed by placing an adhesive sealing means such as a gasket or sealing material around the entire perimeter of the pinchweld and positioning the glass on the sealing means. Chrome moldings are generally mounted over the juncture of pinchweld and glass for decorative concealment, rather than functional purposes.
The pinchweld area is highly vulnerable to water retention and consequent rusting, particularly in the corners. Although rust deterioration of the pinchweld is not ordinarily visible, it manifests itself by water leakage around the windshield. When the automobile is brought in to correct the leakage problem or to replace a cracked windshield and the glass is removed, the previously concealed deterioration is exposed.
Two basic methods of repair have been devised for repair of the deteriorated pinchweld. The solutions are generally either reconstruction with body tapes or fillers or replacement with new body sections. The first method uses a plastic filler to replace rusted metal after grinding away as much rust as possible, and reconstructing the area with the body filler, or sometimes merely with a patching tape. However, body fillers, which are generally synthetic resins, tend to be only a temporary solution, as they are not durable, cannot withstand stress and do not deter further rust propagation around the filler.
The second method uses automobile body sections to replace the damaged area and may be accomplished by various means. For example, the replacement sections could be factory replacements, but these are rarely available and are extremely expensive. More often, an attempt is made to find a salvaged automobile of identical make from which the necessary body portion must be removed by torch cutting and brought to the repair shop. In either case, when the rusted portions have been removed, the replacement section must be laboriously secured in position and in proper registry on the automobile, usually by skillful welding.
Once the replacement part has been secured in the proper position, a great deal of finish work is necessary to smooth the exposed surfaces in an attempt to restore the automobile to its original condition. The removal, replacement, fitting and finish work require a relatively high degree of expertise not generally found in a windshield repair shop, but requiring a skilled body repairman. The cost involved is extremely high.
In the case of rusting of the pinchweld, which is a rather frequent occurrence, new factory replacement panels, even if obtainable, are prohibitive in cost. The option of obtaining and using a body portion from a salvaged automobile may be somewhat less costly, but such salvage parts are not always available when needed and the cost of obtaining and installing such a body part is still relatively high.